The spacecraft has blasted off with three astronauts on board on a 15-day mission to an experimental space lab in the latest step towards the development of a space station.

The Shenzhou 10 spacecraft was launched from a remote site in the Gobi desert in China's far west at 5:38 p.m. local time, in images carried live on state television.

Once in orbit, the craft will dock with the Tiangong (Heavenly Palace) 1, a trial space laboratory module, and the two male and one female astronauts will carry out various experiments and test the module's systems.

They will also give a lecture to students back on Earth.

China successfully carried out its first manned docking exercise with Tiangong 1 last June, a milestone in an effort to acquire the technological and logistical skills to run a full space station that can house people for long periods.

"Right now they're probably getting out of the experimental phase of their space program and they're getting more into an operational phase," space analyst Morris Jones has told Radio Australia's Asia Pacific.

"They've pretty much fixed the design of the Shenzhou spacecraft. They've tested it several times. They've proven that they can operate complex missions and do rendezvous and docking and live in onboard space laboratories for fairly long periods.

"So essentially that's the end of the beginners' course. From now on, they'll gradually ramp up their capabilities for more operational missions."

President Xi Jinping oversaw Tuesday's launch personally, addressing the astronauts before they blasted off to wish them success, saying he was "enormously happy" to be there.

"You are the pride of the Chinese people, and this mission is both glorious and sacred," Xi said, according to state media.

This mission will be the longest time Chinese astronauts have spent in space, and marks the second mission for lead astronaut Nie Haisheng.

You have no doubt been hearing a lot about the Paris Agreement and know that it pertains to climate change, but are too embarrassed at this stage to ask for an overall explanation of what it's all about.